Volume 7, Number 9, Abstract 331, Page 331a doi:10.1167/7.9.331 http://journalofvision.org/7/9/331/ ISSN 1534-7362
Finding signals in noise: The neural advantage of prior information
Scott Gorlin
Department of Brain and Cognitive Sciences, MIT
[e-mail]
Jitendra Sharma
Department of Brain and Cognitive Sciences, MIT, and Picower Institute for Learning and Memory, MIT
Hiroki Sugihara
Department of Brain and Cognitive Sciences, MIT, and Picower Institute for Learning and Memory, MIT
Mriganka Sur
Department of Brain and Cognitive Sciences, MIT, and Picower Institute for Learning and Memory, MIT
Pawan Sinha
Department of Brain and Cognitive Sciences, MIT
Abstract

One of the least understood aspects of mammalian vision is the ability to recognize scenes through significant degradations in image quality. Neural receptive fields have traditionally been described with coherent structures - for example, oriented gratings in V1. However, this does not address how neurons respond to noisy, less coherent visual input, which is arguably more prevalent in the natural world. Previous studies with natural images show that recognition is highly non-linear with respect to noise, and more importantly, that recognition in noise is facilitated by prior experience with the stimuli (Sadr and Sinha, 2004). We extend these studies by using RISE sequences (Random Image Structure Evolution) to present structured images evolving from noise in an fMRI paradigm. Specifically, the direction of RISE evolution - ascending or descending in information content - allows us to control for low-level image features, such as luminance, while trending towards or away from a neuron's experimentally defined preferred stimulus. Any difference in response to ascending and descending stimuli thus reflects prior knowledge facilitating neural recognition in noise. In line with previous behavioral studies, we present evidence for this hysteretic facilitation throughout the visual hierarchy. Furthermore, we show a graded signature of hysteresis from V1 through IT, suggesting that prior knowledge affects lower and higher visual areas in different ways.

History
Received April 27, 2007; published June 30, 2007
Citation
Gorlin, S., Sharma, J., Sugihara, H., Sur, M., & Sinha, P. (2007). Finding signals in noise: The neural advantage of prior information [Abstract]. Journal of Vision, 7(9):331, 331a, http://journalofvision.org/7/9/331/, doi:10.1167/7.9.331.
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